Great list. I found this comment more interesting than the OP, personally. The best addition to the list that I can think of is natural language processing. Ex

Great list. I found this comment more interesting than the OP, personally. The best addition to the list that I can think of is natural language processing. Extracting information from text, especially. There's a ton of interesting pieces, and most of them are useful for one kind of large-scale internet application or another.